This invention relates to both rider energized and motor driven three wheeled vehicles with two steerable wheels in front and one powered rear wheel.
Three wheeled vehicles generally include one steerable front wheel and two powered rear wheels. This three wheeled vehicle design is based on providing stability by three point support for the rider. A two wheeled vehicle utilizes steering as the means to balance the vehicle and provide stability with vehicle and rider leaning against the centrifugal force encountered during a turn. The three wheeled vehicle is highly stable when not moving or moving in substantially a straight line. However, this very stability, with the three support points for existing three wheel vehicles, does not allow for leaning of either the vehicle or rider into a turn as in the case of two wheeled vehicles. The result is that existing three wheeled vehicles are very unstable during turns and frequently roll over or throw the rider outward as a result of the centrifugal force exerted upon the rider and vehicle. In some cases, the rider has been thrown off a three wheeled vehicle during a turn with the vehicle remaining upright resulting in the discarded rider being run over by one of the rear drive wheels.
In order to improve stability, a second rear wheel is sometimes incorporated in converting a two wheeled vehicle to one having three wheels. This arrangement requires a modified drive transmission arrangement, frequently including a differential transmission, as well as an intermediate shaft with an additional chain and sprockets to accommodate a three speed shift transmission. This substantially increases the cost and complexity of the vehicle. A more commercially attractive approach would be to add a second front wheel and retain the single rear drive wheel and thus allow the drive means to be identical to the standard, more efficient bicycle stock drive, with either the ten or five speed derailer transmission to drive the single rear wheel as in the case of a conventional two wheeled vehicle.
The present invention overcomes the aforementioned problems of the prior art by counteracting the centrifugal force exerted upon a vehicle and its rider during a turn. In the present invention the seat moving inward in relation to the amount of turn shifts the center of gravity of the rider inward from a line between where the rear wheel and the outer front wheel contact the road so that the rider's weight has a greater anti-rotational force about the aforementioned line to permit a greater centrifugal force on the rider without the vehicle tipping over or the rider falling outward. Also, in the present invention centrifugal force acting on the rider moves him outward, causing the rear frame to rotate and the front wheels to swing back so as to lessen the sharpness of the turn and prevent the vehicle from rolling over. The present invention may be used in combination with the rear portion of a conventional bicycle having a five-or ten-speed transmission with available derailer and caliper brakes. The present invention may also be employed with the oppositely reciprocating pedal drive system of U.S. Pat. No. 4,561,668, issued to the present inventor, or a motor may be used to drive one or more of the three wheels, or any other means may be used to power the vehicle such as wind against an attached sail.